The Dallas daily herald. [volume] (Dallas, Tex.) 1873-1887, 1887-01-04
Earthquakes really depend upon the


condition of the earth's interior. SO
far, no way has been found to deter
mine this with certainty. If the indica-
tons shown within moderate depths
are reliable, it must be hot enough
within hundred miles of the surface
to melt all common substances. proba-
by so within thirty miles, while tho
pressure is sufficient 10 cause ready
motion, like liqu DIS. The hard crust
is only the part of the earth which has
already cooled down. But the earth
has not yet ceased cooling, and it will
not utill all bodies in the heavens reach
the same temperature. The result of this
cooling is contraction; the whole earth
grows smaller. and this must cause
movements in the solid portion. Even
if the contraction is an exceedingly
small amount, still the cause is sufi-
cient to make frequent movements.
Perhaps some of these motions may at
times allow masses of confined gas to
accumulate and then escape at any
weak point with almost explosive vio-
lence
There is another result which mrst
follow the contraction Of the earth,
and it certainly has followed in the
past upon n magnificent scale. as our
mountains all show it. The different
layers of the earth become bent and
cracked; they are folded over in ali
directions; sometimes they are even
turned up edgewise. The cracking or
turning up of these masses of earth.
often solid rock, limestone, and other
hard materials, would make a most
violent earthquake. Indeed no earth
quake Oh record would begin to COM
pare in violence with what would fol-
low such cracking as is found in many
places in Pennsylvania. Even min
ute slipping of one layer upon the next
would produce tremor which would
be felt as an earthquake wave over very
large areas, and some of the layers in
the Allegheny mountains have slipped
many feet. This may have occurred in
stantly, producing an earthquake OF
untold violence. Or, what is far moro
likely. it may have been produced by
long course Of minute movements, per-
haps separated from one another by
many years.
The data of the last earthquake are
not yet known with sufficient minute
ness to allow their application to the
land along the seaooast so as to ev-
plain all tho questions fully. Ii seems
probable that it was simply a move
ment of one layer upon another at
some point of the line of fracture not
very far from Charleston. Such a
movement of less than one inch would
be sufficient to produce all the changes
so far reported. What particular force.
or combination of forces, caused the
movement to come on August 81, can
not vet be stated and may never be =
known. Some surmise that 1t may
nave Dcen Tue Eltht Ou'hON vi VA an"
gas of the last few years. If this is
correct, an increase in the output OF
gas and oil should follow almost imme-
diatelv. But whether this had part
in producing the phenomenon, or wheth-
err it was due 10 contraction alone. the
earthquake S likely to be followed. by
others because the same condition Of
things remains.
Some surprise has been expressed
that this earthquake was not followed
by great ocean wave at Charleston.
The sea wave is sometimes the most
destructive element Of the earthquake.
Had such a wave followed at Charles
ton, the loss of life would have been
multiplied. But there was nothing to
produce the wave. for tho centre of the
disturbance was on the land side Of the
city, not seward. The sea wave fol-
lows a sudden change of level OF the
floor of the ocean. either rise or a de-
preston. The fact OF its absence at
Charleston shows that the centre Of tho
movement was on the land side lie
Roy r. Griffin. in The CHrrenk